Perspective

Living organisms are complex, and ideas that may seem to be common sense do not always turn out to be useful. Consequently, physicians are taught to use evidence-based medicine, and many studies are performed to test what may seem to be obvious. For example, studies in prisons show that persons who shower more often are less likely to have problems with skin infections caused by MRSA. But surprises come along. For example, sharing bar soap is a risk factor for MRSA infection. Problems arise when decisions must be made in the absence of direct evidence. Many aspects of antibiotic resistance fall into this category, largely because diagnosis of infections at an early stage is difficult and because drug susceptibility testing is not routinely....Box 12-11Table 12-4Table 12-5Table 12-5